This invention relates generally to high-voltage electrical connectors, and, more particularly, to high-voltage connectors having dielectric seals around their electrically connectable contact pins. High-voltage connectors are used in a variety of devices. For example, in coupling a high-voltage power supply to a traveling-wave tube, a connector rated as high as 20 kv may be required. Such a connectcr may, for example, effect connection of a single high-voltage conductor and a surrounding ground conductor, but in other types of connectors, multiple pins may be involved.
In the design of high-voltage connectors of this general type, electrical arcing and corona discharge must be eliminated, or at least minimized. One technique for achieving this goal is to surround the connector contact pins with a dielectric material, thereby isolating the connector from the surrounding atmosphere. Unfortunately, however, the use of dielectric materials, such as natural or synthetic rubber, usually results in significant difficulty in coupling and uncoupling the constituent parts of the connector.
Typically, a high-voltage connector comprises a receptacle assembly and a plug assembly. The receptacle assembly has an insultated body, usually of a ceramic material, and includes a male contact pin recessed relatively deeply inside a cylindrical bore within the insulated body. The plug assembly includes a female contact pin with a bore in its end sized to receive and retain the male contact pin of the receptacle assembly.
In a typical connector of the prior art, a dielectric seal, of rubber or similar material, encases the contact pin on the plug assembly, except for an end hole in which the male pin of the receptacle assembly is inserted. When the connector is assembled, the contact pin in the plug assembly, including the surrounding rubber dielectric seal, is crammed inside the ceramic insulated body of the receptacle assembly, and a lock nut is engaged to retain the two halves of the connector in an assembled relationship.
Unfortunately, however, this type of connector structure has a number of significant disadvantages. Most importantly, connectors of this type simply do not have good performance characteristics at low temperatures and low pressures, such as might be encountered at high altitude in some applications. It has been theorized that some corona discharge still occurs in air gaps around the contact pins. Another disadvantage is that the ceramic material usually used for the insulated receptacle body is an abrasive material, and this results in significant wear on the rubber dielectric seal. In some instances, as few as ten or twelve matings of the connector can have a significant effect on its performance.
In addition, the inner ceramic surface of the receptacle assembly can become soiled by repeated matings with the rubber dielectric seal, and this may also have a detrimental effect on the operation of the connector. Also significant from a wear standpoint, is the abrasive action of a threaded portion of the ceramic insulated body, as it engages the threads of the lock nut.
Another important consideration is that the coupling action requires a relatively large axial force to be applied between the plug and receptacle assemblies, and damage may result to the connections between the conductors and the contact pins of the connector. Such damage can also result from the uncoupling action.
Many of these disadvantages are aggravated when the connector is subjected to low temperatures, and the rubber dielectric material becomes less resilient, more brittle, and more susceptible to wear. Coupling the plug and receptacle assemblies together at low temperatures is particularly difficult and often results in damage to the dielectric material.
It will be appreciated from the foregoing that there is a significant need for an improved high-voltage electrical connector that avoids the aforementioned disadvantages of the prior art, and that provides a connector operable even at low temperatures anmd pressures, and capable of being coupled several hundred times without significant wear. The present invention fulfills this need.